22 THE ALUMNI JOURNAL. 



OIL OF EUCALYPTUS. 



The tabulation of results given in the accompanying table is based 

 on the examination of Oils of Eucalyptus, which are being submitted 

 to the wholesale trade as U. S. P. standards. 



Those oils containing phellandrene, a terpene which the Pharma- 

 copoeia states should not be present to more than a certain extent and 

 which is detected as follows : If 2 c.c. of the oil be mixed with 4 c.c. 

 of glacial acetic acid and 3 c.c. of a saturated aqueous solution of 

 sodfum nitrate be gradually added, the mixture when gently stirred 

 should not form crystals of phellandrene nitrite (from U. S. P.) ; wdl 

 in this case be found low in cyneol and extremely high in optica! 

 rotation. 



The low per cent, of cyneol may be due to the nature of these oils 

 l)nt in some cases it is due to adulteration of the oil by the addition 

 of castor oil. 



The iiigh optical rotation in this case is due to the excessive amount 

 of phellandrene, the optical rotation of which is f 103.1°. 



Samples of this kind are usuall>- detected by their low per cent, of 

 cyneol which usually ranges between 38-40% : their comparative high 

 specific gravity which ranges from o.ot/ to o.()ig: and. lastlv, l)v then- 

 greater viscositv. 



It seems to me, and many other chemists and pharmacists, that the 

 I'harmacopoeia does not go far enough into detail regarding the test for 

 the presence of ]:»hellandrene in Oil of Eucalyptus. 



It only states tint the crystals of phellandrene nitrite should not 

 form. 



To my own estimation it should at least describe the crystals so that 

 one could be more positive of their presence. 



Those who have never seen crystals of phellandrene nitrite as they 

 appear in the test would hardly recognize the yellowish mass which 

 forms as such. 



To the naked eve the mass seems to V.q non-crystalline, liut under the 

 microscope it appears otherwise. 



The crystals then appear colorless acicular and are formed in con- 

 centric clusters. 



Eollowing is a method of isolation and test of identity sufficient to 

 yivove the presence of i-)hellan(1rene in this case and many others: 



